Embryogeny ofPhaseolus coccineus: Growth and microanatomy

Summary During early embryogeny, the development of the suspensor is rapid both in terms of size and fresh weight; structural differentiation can be observed as early as the proembryo stage with the formation of wall ingrowths. Ingrowths first appear in the outer wall of the suspensor cells adjacent to the integumentary tapetum, soon ingrowths begin to form in the inner suspensor cells as well. A basal-terminal gradation in nuclear size exists, with the largest nuclei in the basal suspensor cells. Cytologically, the suspensor cells appear to be very active, especially when the embryo reaches heart stage. Initially, the development of the embryo proper lags behind the suspensor, but its size and fresh weight increase rapidly as development proceeds. The volume of the liquid endosperm rises most rapidly during the late heart stage; and it is absorbed soon after. A cellular endospermic sheath surrounds the embryo, separating it from the liquid endosperm. Structural differentiation also occurs in the cellular endosperm cells with the formation of wall ingrowths in those cells that abut directly onto the integumentary tapetum. Both the suspensor and the cellular endosperm appear to remain active through the maturation of the seed. Storage bodies are formed in the cotyledons as well as in the embryonic axis. In the suspensor and the cellular endosperm, starch grains and lipid bodies can be found at the maturation stage.     

Bone marrow-derived cells: A potential approach for the treatment of xerostomia

Transplantations of bone marrow-derived cells (BMDCs) are traditionally used for hematologic diseases, but there are increasing numbers of clinical trials using BMDC treatments for non-hematologic disorders, including autoimmune diseases. BMDCs are recently reported to improve organ functions. This paper will review available reports supporting the role of BMDCs in reducing xerostomia (i.e. re-establishing salivary gland functions) due to head and neck irradiation for cancer therapies and in Sj?gren's syndrome. There are reports that BMDCs provide a beneficial effect on the saliva production. BMDCs positively affect blood vessels stability and regeneration in irradiated salivary glands. Also, BMDCs provide an immunomodulatory activity in mice with Sj?gren's-like disease. While the exact mechanisms by which BMDCs improve organ functions remain controversial, there is preliminary evidence that a combination of them (such as cell transdifferentiation, vasculogenesis, and paracrine effect) occur in salivary glands.     

A quantitative and descriptive approach to morphological variation of the endocranial base in modern humans

The cranial base is one of the major foci of interest in functional craniology. The evolution and morphogenesis of this structure are still poorly known and rather controversial because of multifactorial influences and polyphasic stages. Endocranial dynamics are associated anteriorly with the upper facial structures, laterally with the mandibular system and midsagittally with brain development. In the present study, we investigated the endocranial morphology of modern humans using 3D landmark-based approaches, i.e. geometric morphometrics and Euclidean distance matrix analysis. The structure of endocranial variation is poorly integrated, with only weak reciprocal influences among the three fossae. Some major variations are associated with changes in the posterior fossa, with possible consequences on the anterior areas. These main patterns of integration are hypothesized to be influenced by the connective tensors of the dura layers. Static allometry and sex differences are largely related to the ontogenetic sequences, characterized by early maturation of the anterior fossa with respect to the middle and posterior regions (i.e., relatively shorter posterior part of the planum sphenoideum and vertical lengthening of the clivus in males). The relative independence between the endocranial fossae, as well as their structural connection through the meningeal tensors, must be carefully considered in studies on the evolutionary dynamics, since they lead to mosaic changes through phylogeny.     

Dynamic and static views of succession: Testing the descriptive power of the chronosequence approach

Chronosequence and permanent plot studies are the two most common methods for evaluating successional dynamics in plant communities. We combined these two approaches by re-sampling an old-field chronosequence at Cedar Creek Natural History Area (Minnesota, USA) to: (1) measure rates of secondary succession; and (2) to test the ability of the chronosequence approach to predict actual successional dynamics over a 14-year survey interval. For each of 19 chronosequence fields we calculated four complimentary indices of succession rate for community changes that actually occurred within each of these fields between 1983 and 1997. We found that measures of compositional dissimilarity, species turnover, and the change rates of perennial and native species cover over this 14-year period were all negatively correlated with field age, indicating that the rate of successional change in these old-fields generally declines over time. We also found that data collected from the initial static chronosequence survey (1983) accurately predicted many of the observed changes in species abundance that occurred between 1983 and 1997, but was a poor predictor of changes in species richness. In general, chronosequence re-sampling confirmed the validity of using the chronosequence approach to infer basic patterns of successional change.     

Palaeohistology and external microanatomy of rauisuchian osteoderms (Archosauria: Pseudosuchia)

Abstract: The presence of postcranial dermal armour is plesiomorphic for Archosauria. Here, we survey the external microanatomy and histology of postcranial osteoderms (i.e. dorsal paramedian and caudal osteoderms) of rauisuchians, a widely distributed assemblage of extinct predatory pseudosuchians from the Triassic. The osteoderms of eight rauisuchian taxa were found to be rather compact bones, which usually lack significant bone remodelling or large areas of cancellous bone. The presence of highly vascularized woven or fibrolamellar bone tissue deposited in the core areas indicates higher growth rates during earlier life stages, whereas a more compact parallel‐fibred bone matrix indicates reduced growth rates in later development. This pattern of change corroborates earlier studies on long bone histology. With the exception of a bone tissue found in the sample of Batrachotomus kupferzellensis, which might be the result of metaplastic ossification, the general mode of skeletogenesis is comparable with intramembraneous ossification. The lack of cancellous bone tissue and remodelling processes associated with bone ornamentation, as well as the predominantly intramembraneous mode of ossification, indicates that rauisuchian osteoderm formation differs profoundly from that of the osteoderms of the only extant pseudosuchian lineage, the crocodylians.     

Reassessing the spatial relationship between sponges and macroalgae in sublittoral rocky bottoms: a descriptive approach

Because sublittoral sponges of temperate areas are usually more abundant at sites with low algal abundance, there is the widespread notion that macroalgae out-compete and displace sponges to habitats less suitable for algal proliferation. In this study, based on 292 sampling quadrats, we collected a total of 87 demosponge species and examined the level at which sponge distribution pairs with a variety of alga-dominated and animal-dominated habitats occurring in three zones located across a marked in-bay/out-bay environmental gradient. We found significant differences in sponge biomass, richness and diversity between the 18 habitats considered in the three zones, with abundance, richness and diversity being significantly higher in caves, vertical surfaces and overhangs out of the bay than in the remaining habitats. The cluster analysis and the unconstrained ordination consistently reflected the in-bay/out-bay environmental gradient. These analyses also revealed that the taxonomic distribution of sponge abundance is independent of the algal occurrence in the habitat, being more related to between-zone differences than to between-habitat differences. This trend was corroborated when the role of depth, algal abundance and substratum inclination in explaining total sponge abundance and diversity was examined by canonical correspondence analysis, regression analysis and mean comparisons. These analyses pointed to substratum inclination, rather than to algal abundance, as the factor explaining most variation in distribution of sponge abundance. These results, when discussed in the context provided by the outcome of other studies concerned with the spatial distribution of the sessile benthos in rocky temperate communities, strongly suggest a need to re-examine the idea that spatial distribution of sublittoral sponges largely results from competition with macroalgae.     

A new and simple method for studying the microanatomy of nephrons and collecting tubules

A simple procedure for studying the microanatomy of the kidney by light microscopy is described. Specimens are dried by the critical-point method and later impregnated with a mounting medium. The retention of air within the lumen of nephrons and collecting tubules permits their visualization. The method allows the observation of renal microanatomy without the distortions produced by microdissection or the loss of structural relationships among different kidney components. It also permits observation of the same specimen by both light and scanning electron microscopy.     

Thermo-search: lifestyle and thermostability analysis

Thermo-search is an online web tool for the analysis of proteomes and individual proteins according to the ratio of two couplets of preferred and avoided amino acids in hyperthermophiles, thermophiles and mesophiles. It displays the ratio between glutamic acid plus lysine (E+K) and glutamine plus histidine (Q+H), which is higher in thermophilic proteomes and thermostable proteins than in mesophilic proteomes and thermo labile proteins. Thermo-search allows a rapid screen of the CRM database for thermostable proteins in their functional categories and a visualization of the (E+K)/(Q+H) average ratio between organisms, allowing a comparison of their lifestyles.     

Brachymesophalangia-V in five samples of children: A descriptive and methodological study

The occurrence of brachymesophalangia-V (BMP-V) in 2,012 individuals from five samples of children of different ethnic backgrounds was determined using two indices. Frequencies of BMP-V were analyzed for three variants: BMP-V alone, BMP-V with clinodactyly, and BMP-V with a cone-shaped epiphysis. The two indices used to identify BMP-V indicated highest relative frequencies among Mexican children, moderate frequencies among children of European ancestry (Pennsylvania White, Canadian, West German), and lower frequencies in Pennsylvania Black children. Index 1, based on the ratio of the width to the length of the fifth mid-phalanx, consistently produced higher frequencies than Index 2, based on the ratio of the length of the fifth to the length of the fourth midphalanges. Index 1 was also more selective of BMP-alone, while Index 2 selected primarily BMP-V with clinodactyly and/or cone-shaped epiphyses. The differences between indices were largely due to the fact that Index 1, which basically defines shape, selected both the shortest and/or widest mid-phalanges, while Index 2 related actual length differences. It is suggested that Index 2 provided a more suitable criterion of BMP-V in comparative studies, due to possible population differences in phalangeal shape.     

Gastrointestinal disseminated histoplasmosis in HIV-infected patients: A descriptive and comparative study

Disseminated histoplasmosis is one the main AIDS-defining opportunistic infections in HIV-infected patients, notably in Latin America. The non-specific and proteiform clinical presentation leads to diagnostic delays that may lead to fatal outcomes. This retrospective multicentric study aimed to describe the frequency and manifestations of gastrointestinal histoplasmosis in French Guiana, and to compare patients with disseminated histoplasmosis with or without gastrointestinal involvement.Between January 1, 1981 and October 1, 2014 co-infections with HIV and histoplasmosis were enrolled. Inclusion criteria were: age >18 years, confirmed HIV infection; first proven episode of histoplasmosis.Among 349 cases of disseminated histoplasmosis, 245 (70%) had a gastrointestinal presentation. Half of patients with gastrointestinal signs had abdominal pain or diarrhea, mostly watery. Half of patients with abdominal pain had diarrhea (63/124) and half of those with diarrhea (63/123) had abdominal pain. A significant proportion of patients also had hepatomegaly and, to a lesser degree, splenomegaly. After adjusting for potential confounding, the presence of lymphadenopathies >2cm (AOR = 0.2, IC95 = 0.04–0.7, P = 0.01), Haitian origin (AOR = 0.04, IC95 = 0.004–0.4, P = 0.006) were associated with a lower prevalence of gastrointestinal signs and positive gastrointestinal presence of H. capsulatum. Persons with a gastrointestinal H. capsulatum were more likely to have a decreased prothrombin time, lower ferritin, lower liver enzymes, and lower concentrations of LDH than those without gastrointestinal signs and symptoms. They also had a shorter interval between symptoms onset and diagnosis. Patients with a positive gastrointestinal identification of H. capsulatum were less likely to die at 1 month than those without a gastrointestinal presentation (respectively, 4.6% vs 18.5%, P = 0.01).Subacute or chronic gastrointestinal presentations are very frequent during disseminated histoplasmosis, they seem less severe, and should lead to suspect the diagnosis in endemic areas. There were populational or geographic differences in the frequency of gastrointestinal manifestations that could not be explained.     

The Ventral Photoreceptor Cells of Limulus : I. The microanatomy

The ventral photoreceptor cells of Limulus polyphemus resemble the retinular cells of the lateral eyes both in electrical behavior and in morphology. Because of the great size of the ventral photoreceptor cells they are easy to impale with glass capillary micropipettes. Their location along the length of the ventral eye nerve makes them easy to dissect out and fix for electron microscopy. Each cell has a large, ellipsoidal soma that tapers into an axon whose length depends upon the distance of the cell from the brain. The cell body contains a rich variety of cytoplasmic organelles with an especially abundant endoplasmic reticulum. The most prominent structural feature is the microvillous rhabdomere, a highly modified infolding of the plasmalemma. The microvilli are tightly packed together within the rhabdomere, and quintuple-layered junctions are encountered wherever microvillar membranes touch each other. Glial cells cover the surface of the photoreceptor cell and send long, sheet-like projections of their cytoplasm into the cell body of the photoreceptor cell. Some of these projections penetrate the rhabdomere deep within the cell and form quintuple-layered junctions with the microvilli. Junctions between glial cells and the photoreceptor cell and between adjacent glial cells are rarely encountered elsewhere, indicating that there is an open pathway between the intermicrovillous space and the extracellular medium. The axon has a normal morphology but it is electrically inexcitable.     

The miracidium microanatomy of Philophthalmus rhionica (Trematoda: Philophthalmidae)

The study of ultrastructure of Philophthalmus rhionica miracidium was carried out. Update the ultrastructures of miracidium were studied in a restricted number of species belonging to the families Notocotylidae, Paramphistomatidae, Sanguinicolidae, Fasciolidae, Schistosomatidae (Galaktionov, Dobrovolsky, 1998). The ultrastructure of representatives of two latter families, Fasciola hepatica and Schistosoma mansoni respectively, have been examined most carefully. The family Philophthalmidae differs from the families Fasciolidae and Schistosomatidae by the aberrant pedogenetic miracidium.     

Symmetry applied to nuclear microanatomy: a review of gene function and cell differentiation

The purpose of this paper is to review current knowledge and understandings of gene control and cell differentiation, based upon an appreciation of a possible role that nuclear microanatomy and considerations of steric symmetry might play. Metaphase sister chromatids have identical base codes but show a mirror image symmetry of higher order coiling. Chromosomes in the interphase nucleus have spatially well defined domains and are anatomically distinct and ordered. Chromosomes are known to have interactions i.e. sex chromosome inactivation, PEV, etc. An hypothesis of gene activation is made based on steric interactions among chromosomes and between chromosomes and activating and repressor proteins. These interactions may be influenced by the handedness of higher order chromatid coiling, since homologues show mirror-image symmetrical coiling in metaphase, which might be retained to a certain degree in interphase. This may result in a binary switching of genes. All possible combinations of chromatids in the interphase nucleus, would be enabled by a differential segregation of homologous chromatids at mitosis. To conserve patterns of interchromatid interactions, there must be a programmed segregation of chromatids towards one of the two spindle pole attachments. This orientation might be effected by preferential attachment of microtubules to kinetochore attachment sites, by steric hindrance of the kinetochore by condensed chromatin which initially allows only unidirectional tubule attachment, or possibly by a tethering of interacting chromatids which would migrate en masse. An attempt to apply this hypothesis to some illustrative pathological conditions is made.     

Healthy lifestyle and breast cancer risk: A case-control study in Morocco

BackgroundSome modifiable risk factors have been independently associated with breast cancer (BC) risk in Moroccan women, but no studies have investigated their joint association. This study aimed to investigate the association between a Healthy Lifestyle Index (HLI) score and BC risk among Moroccan women.MethodsIn this case–control study, 300 incident BC cases and 300 controls, matched by age and area of residence were recruited. Cases were women newly-diagnosed with histopathologically–confirmed BC at the University Hospital in Fez, Morocco. Controls were randomly selected healthy women recruited from 6 primary health centers in Fez. HLI scores developed within this study were assigned to participants based on 11 factors (red and processed meat, white meat, cream, cheese, fish, fruit and vegetables, physical activity, BMI, smoking, alcohol consumption, and breastfeeding), where 0 was given to unhealthy and 0.5 or 1 to healthy levels of each factor. Conditional and unconditional logistic regression models were used to assess the association between HLI scores and BC risk.ResultsMean of HLI scores were 8.1 (±1.1) and 9.0 (±0.9) in cases and controls, respectively, p < 0.01. After adjusting for potential confounders, one-point increment in the HLI score was associated with 56% (95% CI, CI: 39–68%), 49% (95% CI: 30–63%), and 59% (95% CI: 40–72%) lower risks of BC in all, premenopausal, and postmenopausal women, respectively.ConclusionHigh HLI scores were associated with decreased risk of BC in Moroccan women. These findings suggest that BC prevention policies should include strategies for engaging Moroccan women in healthy lifestyles.     

Origin and development of stomatal microanatomy in two species ofEucalyptus

Summary Development of the stomata ofEucalyptus orbifolia (in which they are relatively superficial) andE. incrassata (in which they are deeply sunken) is described from light microscopy of thin sections of resin-embedded material. The envelope of the guard mother cell is retained intact while in the daughter cells (guard cells) the inner and outer thickenings are formed. The mother cell envelope may even remain discrete and intact during early stages of formation of the separation spaces, precursors of the future stomatal pore, between the thickenings. Remnants of the guard mother cell wall may be retained as parts of at least the inner stomatal ledges. Likewise, remnants of the wall which divides the mother cell persist on the maturing guard cells.Sudan III-positive materials, probably cutin, are removed from the cuticle over the mother cell soon after it is formed. The cuticle above the guard cell is finally perforated by enzymic attack forming, inE. incrassata, a large cavity outside the developing stoma into which the outer stomatal ledges grow as extensions of the upper guard cell walls.The termostiole is suggested for the aperture in the cuticle. The flanges of cuticle seen in section to bound it are termedostiolar ledges. The ostiolar ledges are to be distinguished from the outer stomatal ledges, which develop from the upper thickenings of the guard cell initials. The distinction is clear inE. incrassata (and other species with deeply sunken stomata) but not in mesophytic plants or species with superficial stomata such asE. orbifolia in which the outer stomatal ledges are fused with the cuticle.Growth of the outer stomatal ledges inE. incrassata involves transport of wall materials through an annular space, the equivalent of an ectocythode.The relevance of the observations to stomatal development in other genera is discussed.